JOHNNY Ruffo revealed his shocking brain cancer diagnosis last month but what he didn't say was how close he actually came to dying.

Speaking to New Idea today, the Home and Away star has spoken for the first time about his terrifying close call and how the surgery helped save his life.

"Without the operation, there was a 100% certainty I would have died because of the pressure on my brain," he said.

Ruffo headed to Prince Alfred Hospital mid last month because of a migraine where doctors instead discovered a brain tumour and immediately admitted him for emergency surgery.

While they managed to remove 95% of the tumour, they had to leave 5% behind, due to its proximity to nerve endings.

"If they had tried and something went wrong, it could potentially have caused paralysis all down the left side of my body," he said.

For a number of days following the surgery, the former X Factor star revealed he struggled to speak.

"I was talking garbage, even worse than usual (laughs). But within days I was back to being myself again. I felt a lot better, lighter. I was confident, I was just sure it was all fine. The tumour was going to be benign, no problem," he said.

This photo shocked users on Instagram when Johnny Ruffo posted it to his account after his surgery.

Unfortunately, further tests revealed the tumour was malignant. He also soon learned that the specific cancer was an incredibly rare type that only affects three per cent of brain cancer sufferers.

But despite the diagnosis, Ruffo has started an aggressive course of treatment and is staying positive.

"There was a lot of medical jargon, but by all accounts this responds really well to radiotherapy and chemo so they are pretty confident they can beat it, which is good news," he told the magazine.

Ruffo, who shot to fame after coming third on The X Factor in 2011, will do six weeks of radiation, have a month break, and then most likely have months of chemotherapy.

"Hopefully, I'll be home and hosed after that," he ended.

The singer revealed his shock diagnosis in an Instagram post last month, sharing images of a dramatic post-surgery scar across his forehead and another of his head bandaged while sitting in a hospital bed.

"On Sunday I went into hospital with a migraine," Ruffo said in a statement.

"I had to have a brain tumour removed. I am on the mend and feeling positive. Keep me in your thoughts."